There’s a certain star quality to John Devine’s 1966 Chevrolet Chevelle, a Corvette-powered knockout that recently emerged, transformed, from a one-owner cream puff with an 8-cylinder engine and 15,000 original miles. The marketing department at General Motors once called the midsize Chevelle "The Beautiful In-Betweener"; the car was slotted in the Chevrolet lineup between the compact Chevy II and the full-size Impala. It’s a tagline that rings especially true for this fine example, more than 40 years on, although for a reason unrelated to its size. This is a car parked between two eras. On one hand, it is a largely intact depiction of 1960s Detroit style and comfort as defined by Bill Mitchell, GM’s chief stylist from 1958 until 1977. On the other hand, it is an unabashedly modern performer, with the 505 hp heart of a 21st-century supercar.

When Devine, a retired vice-chairman and CFO of GM, conferred with famed hot-rodder Pete Chapouris of the So-Cal Speed Shop about building a car, the possibilities included an early Camaro and a ’50s-era pickup. But Chapouris had a different notion. "I love the lines of the ’66 Chevelle, but I never had the opportunity to build one," he says. "The car is beautiful yet basic, and offers lots of room under the hood. It’s a near-perfect hot-rod platform." Devine was sold. Planning commenced, and in the summer of 2004, Chapouris and company tracked down and claimed an achingly original donor car in Portland, Ore., which they rolled into the Speed Shop’s garage in sunny Pomona, a working-class burg on the eastern edge of Los Angeles County.

Simply stated, the So-Cal Speed Shop is hot-rod heaven. It’s Santa’s Workshop, sans elves (unless they were hiding during our visit). A big, slab-sided warehouse with a big, slab-sided garage behind it, the Speed Shop’s headquarters is not unlike most every other building on this stretch of Grand Avenue, a block from the railroad tracks. Behind that flat facade, however, filling every nook and cranny of 30,000 square feet, is the stuff of hot-rod dreams.

For the uninitiated, a brief primer: The original So-Cal Speed Shop opened its doors on Olive Avenue in Burbank, Calif., on March 3, 1946—the very day its founder, an intense 24-year-old named Alex Xydias, received his discharge from the Army Air Corps. Xydias had a taste for speed, and quickly made a name for himself in the cockpit of a four-wheel projectile known simply as the Belly Tank. Made from the 315-gallon wing-mounted auxiliary fuel tank of a World War II–era P-38 fighter plane, the Speed Shop’s bubble-canopied lakester touched a hair below 140 mph on California’s dry El Mirage lakebed and landed on the cover of the January 1949 issue of Hot Rod magazine.

Xydias and his Speed Shop topped record after record in subsequent years, and earned a devoted following among hard-core rodders during the 1950s. In 1953, with a string of land-speed conquests on his resume, Xydias entered the burgeoning world of drag racing, fielding a chopped-and-channeled ’34 Ford coupe called the Double Threat (named because it was built for both dry-lakebed speed runs and quarter-mile sprints).

The car was an instant winner, making the cover of Hot Rod and setting a string of records, until tragedy struck in 1954. On a drag run (coincidentally in Pomona), the coupe’s clutch exploded and the car burst into flames, severely burning driver Dave DeLangton, who later died from his injuries. Heartsick, Xydias abandoned racing; in 1964 he pulled down the Speed Shop’s garage door for good, leaving the hot-rod business for automotive movie-making and magazine publishing.

Enter Pete Chapouris. Now a fit 66-year-old, he chats about custom cars with the intensity and giddiness of a teenager in cuffed jeans and penny loafers—exactly the guy he was when he built his first hot rod, a ’31 Ford coupe, in 1959. "My dad turned me on to rods and customs at birth, so you could say I didn’t have much of a chance at any other career," he says.

A hot-rod legend in his own right, Chapouris had in 1974 created a glorious customized ’34 Ford three-window coupe called the California Kid for a Martin Sheen movie of the same name. That same year, with fellow rodder Jim "Jake" Jacobs, he founded Pete and Jake’s Hot Rod Parts. But even with all his successes, the So-Cal Speed Shop loomed large in his imagination. "When I was a kid I used to read my dad’s car magazines," says Chapouris, "and two of the coolest people I read about were National Hot Rod Association founder Wally Parks and So-Cal Speed Shop founder Alex Xydias." In 1988, Chapouris and Xydias finally met—and, no surprise, became fast friends—and in 1997 they forged an agreement to revive the So-Cal Speed Shop name and its venerable red-and-white livery and recast the business for a new generation of speed freaks.

There’s no denying that the modern So-Cal Speed Shop is a bustling place, with a thriving mail-order parts business, a garage full of customer cars and trucks in various stages of completion, and a few surprise projects tucked away here and there. And unless appearances deceive, the team, led by shop manager Ryan Reed, is as content as can be. That harmony has a lot to do with Chapouris himself. More than just the big boss, he is happy to be a member of the crew, too, bleeding a brake line or turning a wrench when the need arises. "One of the keys to a healthy car shop," he says, "is having the old guy comfortable with teaching the young guy the tricks of the trade. When it’s right, it’s magic."

In the main garage, an unpainted ’33 Ford four-door sedan with a Chevy V-8 floats on jack stands as it is readied for a two-and-a-half-inch chop job. Nearby is a superb ’55 Ford F100 pickup with a big-block SVO Ford and an oak floor in the bed (a truck which, like the ’66 Chevelle, belongs to John Devine), as well as a ’58 Thunderbird owned by rod fanatic Billy F Gibbons of the band ZZ Top. Ground-up jobs can take a year or more to complete, and can require a seven-figure investment, but the design and craftsmanship—from metalwork and power-train installation to paint, trim, glass, and upholstery—are incomparable. "The Speed Shop’s car-building success lies in the eclectic project choices and the different design parameters attached to each car," says Chapouris. "No two are alike."

Through the open door of another nearby garage gleams the original Belly Tank, restored to perfection, and the Speed Shop’s signature car, a Chapouris-rendered ’32 Ford high-boy roadster called the So-Cal Special (currently without a windshield, and newly modified to accept a snap-on canvas tonneau cover). An adjacent space contains a radically chopped Chevrolet HHR, a mid-engine, tube-frame monster built to assault the land-speed record on Utah’s Bonneville Salt Flats. This is the second such HHR from the shop; the original car (created with General Motors) crashed on the salt in 2006 at nearly 250 mph. (The driver, GM engineer Jim Minneker, walked away from the wreck unharmed—perhaps the ultimate testament to the Speed Shop’s engineering and workmanship.)

For John Devine’s sensational ’66 Chevelle, the Speed Shop doctors determined, naturally, that the donor car’s 283 cu in V-8 had to go. In its place, a Chevy LS7 crate engine provides the motivation—plenty of it. As it does in the overachieving Corvette Z06, the 7.0-liter aluminum-block V-8, hand-assembled at the GM Performance Build Center in Wixom, Mich., produces 505 hp and 470 ft lbs of torque. That prodigious power is directed to the rear wheels through a T56 6-speed manual transmission from a Camaro and a stout aluminum driveshaft from Inland Empire Driveline.

The body was barely modified from stock, altered only to accommodate the Corvette power train and upgraded brakes, steering, and suspension. Visual clues to the car’s modern muscle aren’t hard to spot, however. Eighteen-inch Muroc III rims from Budnik Wheels finished in two-tone satin nickel are surrounded by Z-rated Dunlop SP Sport 9000 tires. A custom-fabricated stainless-steel exhaust system with MagnaFlow mufflers conducts the LS7’s symphony to the rear, playing through a pair of fat tips beneath the nickel-plated bumper.

Like the body, this custom Chevelle’s interior is remarkable in its fidelity to the original. From a plump bucket seat wrapped in buttery, saddle-toned leather, the driver faces a stock steering wheel and dashboard, brightened by a slender, engine-turned stainless-steel insert and satin nickel trim—elements artfully repeated on the center console, from which sprouts a ball-topped shifter with a boot made of the same brown leather. The floors are covered in a square-weave wool carpeting from Germany.

As Chapouris describes the car, recounting the build process and giving nods to various participants (Gabe’s Street Rod Custom Interiors, for instance), his enthusiasm grows to a fever pitch. And yet he’s reluctant to trumpet his own brilliance. "If I have a talent, if there is any genius to any of this, it’s being able to visualize just about anything finished," he says.

From his modest office at the top of the stairs, a space cluttered with stacks of magazines, trophies, scale models, autographed pictures, and framed posters, Chapouris contemplates his career—and his status as one of the patron saints of the rod-and-custom movement—with unexpected modesty. "Hot-rodding is a perfect place for an unemployable guy like me," he says. "It’s sort of like being paid to play baseball." Here’s to another home run.